Power supply unit for aerosol inhaler

ABSTRACT

A power supply unit for an aerosol inhaler includes: a power supply able to discharge power to a load for generating an aerosol from an aerosol source; a connector able to be electrically connected to an external power supply; and a control device configured to control at least one of charging and discharging of the power supply or configured to be able to convert power which is input from the connector into charging power for the power supply. The power supply unit further includes a zener diode which is provided between the connector and the control device so as to be connected in parallel with the control device, and a maximum value of zener voltage of the zener diode is lower than a maximum operation guarantee voltage of the control device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior U.S. provisional application No. 62/793,551, filed on Jan. 17, 2019 and prior Japanese patent application No. 2019-035981, filed on Feb. 28, 2019, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a power supply unit for an aerosol inhaler.

BACKGROUND ART

In Patent Literature 1, a non-combustion type flavor inhaler including an atomizing unit having a load for atomizing an aerosol source without combustion, and a power supply unit including a power supply for supplying power to the load is disclosed.

In general, a power supply unit includes not only a power supply but also a connector that can be electrically connected to an external power supply, and a control device (a control unit, a charger, and so on) that is configured to control at least one of charging and discharging of the power supply or that is configured to be able to convert power which is input from the connector into charging power for the power supply. For example, in Patent Literatures 2 and 3, a power supply unit which includes a zener diode that is provided between a connector and a charger so as to be connected in parallel with the charger in order to stabilize voltage to be input to the charger is disclosed.

[Patent Literature 1] WO 2018/163261 A1

[Patent Literature 2] CN 206865186 U

[Patent Literature 3] CN 104348214 A

However, even though a zener diode is provided, the zener voltage of the zener diode may cause inappropriate voltage to be supplied to the control device.

An object of the present invention is to provide a power supply unit for an aerosol inhaler capable of appropriately protecting a control device.

SUMMARY OF INVENTION

According to an aspect of the invention, there is provided a power supply unit for an aerosol inhaler, the power supply unit comprising: a power supply able to discharge power to a load for generating an aerosol from an aerosol source; a connector able to be electrically connected to an external power supply; and a control device configured to control at least one of charging and discharging of the power supply or configured to be able to convert power which is input from the connector into charging power for the power supply, wherein the power supply unit further includes a zener diode which is provided between the connector and the control device so as to be connected in parallel with the control device, and a maximum value of zener voltage of the zener diode is lower than a maximum operation guarantee voltage of the control device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an aerosol inhaler equipped with a power supply unit of an embodiment of the present invention.

FIG. 2 is another perspective view of the aerosol inhaler of FIG. 1.

FIG. 3 is a cross-sectional view of the aerosol inhaler of FIG. 1.

FIG. 4 is a perspective view of the power supply unit in the aerosol inhaler of FIG. 1. FIG. 5 is an exploded perspective view illustrating the internal configuration of the power supply unit in the aerosol inhaler of FIG. 1.

FIG. 6 is a block diagram illustrating the main part configuration of the power supply unit in the aerosol inhaler of FIG. 1.

FIG. 7 is a schematic diagram illustrating the circuit configuration of the power supply unit in the aerosol inhaler of FIG. 1.

FIG. 8A is a circuit diagram including a zener diode.

FIG. 8B is an explanatory view illustrating the breakdown voltage of the zener diode.

FIG. 8C is an explanatory view illustrating pulsation of input voltage for a charger.

FIG. 8D is an explanatory view illustrating voltage stabilization attributable to the zener diode.

FIG. 9 is an explanatory view illustrating a range of zener diodes suitable as a second zener diode (or a first zener diode) of the power supply unit in the aerosol inhaler of FIG. 1.

FIG. 10 is an explanatory view illustrating the operation principle of a smoothing capacitor of the power supply unit in the aerosol inhaler of FIG. 1.

FIG. 11 is a circuit diagram including a low pass filter.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a power supply unit for an aerosol inhaler according to an embodiment of the present invention will be described. First of all, an aerosol inhaler equipped with the power supply unit will be described with reference to FIG. 1 to FIG. 3.

(Aerosol Inhaler)

An aerosol inhaler 1 is a device for inhaling a flavor without combustion, and has a rod shape extending along a certain direction (hereinafter, referred to as the longitudinal direction A). The aerosol inhaler 1 includes a power supply unit 10, a first cartridge 20, and a second cartridge 30 which are arranged in the order along the longitudinal direction A. The first cartridge 20 can be attached to and detached from the power supply unit 10, and the second cartridge 30 can be attached to and detached from the first cartridge 20. In other words, the first cartridge 20 and the second cartridge 30 can be individually replaced.

(Power Supply Unit)

The power supply unit 10 of the present embodiment includes a power supply 12, a charger 13, a control unit 50, various sensors, and so on inside a cylindrical power supply unit case 11, as shown in FIG. 3 to FIG. 6. The power supply 12 is a chargeable secondary battery, an electric double-layer capacitor, or the like, and is preferably a lithium-ion battery.

On a top part 11 a of the power supply unit case 11 positioned on one end side in the longitudinal direction A (the first cartridge (20) side), a discharging terminal 41 is provided. The discharging terminal 41 is provided so as to protrude from the top surface of the top part 11 a toward the first cartridge 20, and is configured to be able to be electrically connected to a load 21 of the first cartridge 20.

Further, on a part of the top surface of the top part 11 a in the vicinity of the discharging terminal 41, an air supply part 42 for supplying air to the load 21 of the first cartridge 20 is provided.

On a bottom part 11 b of the power supply unit case 11 positioned on the other end side in the longitudinal direction (the opposite side to the first cartridge 20), a charging terminal 43 able to be electrically connected to an external power supply 60 (see FIG. 7) capable of charging the power supply 12 is provided. The charging terminal 43 is provided on the side surface of the bottom part 11 b, such that at least one of USB terminals, micro USB terminals, and Lightning (registered as a trade mark) terminals can be connected thereto.

However, the charging terminal 43 may be a power receiving part able to receive power from the external power supply 60 in a non-contact manner. In this case, the charging terminal 43 (the power receiving part) may be composed of a power receiving coil. The wireless power transfer system may be an electromagnetic induction type, or may be a magnetic resonance type. Also, the charging terminal 43 may be a power receiving part able to receive power from the external power supply 60 without any contact point. As another example, the charging terminal 43 may be configured such that at least one of USB terminals, micro USB terminals, and Lightning (registered as a trade mark) terminals can be connected thereto and the above-mentioned power receiving part is included therein.

In other words, the discharging terminal 41 and the charging terminal 43 are separately configured, and are disposed apart from each other in the longitudinal direction A. Therefore, the power supply unit 10 is configured such that in a state where discharging of the power supply 12 through the discharging terminal 41 is possible, it is possible to electrically connect the external power supply 60 to the charging terminal 43. Also, in the power supply unit 10, in a state where the charging terminal 43 and the external power supply 60 are electrically connected, if an aerosol generation request is detected, it is prohibited to perform charging and discharging of the power supply 12 at the same time.

Also, on the side surface of the top part 11 a of the power supply unit case 11, an operation unit 14 which the user can operate is provided so as to face the opposite side to the charging terminal 43. More specifically, the operation unit 14 and the charging terminal 43 are symmetric with respect to the point of intersection of a straight line connecting the operation unit 14 and the charging terminal 43 and the center line L of the power supply unit 10 in the longitudinal direction A. The operation unit 14 is composed of a button type switch, a touch panel, or the like, and is used to activate and shut off the control unit 50 and various sensors and perform other operations according to the intention of a user to use. In the vicinity of the operation unit 14, the control unit 50 and an inhalation sensor 15 for detecting puff actions are provided.

The charger 13 controls charging power to be input from the charging terminal 43 to the power supply 12. The charger 13 is configured with a charging IC including a converter for converting direct current, which is applied from an inverter 61 or the like provided for converting alternating current into direct current on a charging cable which is connected to the charging terminal 43, into direct current having a different magnitude, a voltmeter, an ammeter, a processor, and so on.

The control unit 50 is connected to the charger 13, the operation unit 14, various sensor devices such as the inhalation sensor 15 for detecting puff (inhalation) actions, a voltage sensor 16 for measuring the voltage of the power supply 12, and so on, and a memory 18 for storing the number of puff actions, the time for which power has been applied to the load 21, and so on, as shown in FIG. 6, and performs a variety of control on the aerosol inhaler 1. The inhalation sensor 15 may be compose of a capacitor microphone, a pressure sensor, or the like. The control unit 50 is specifically a processor (a micro controller unit (MCU)). The structure of this processor is more specifically an electric circuit configured by combining circuit elements such as semiconductor elements and so on. The details of the control unit 50 will be described below.

Also, in the power supply unit case 11, an air intake (not shown in the drawings) for taking in air is formed. The air intake may be formed around the operation unit 14, or may be formed around the charging terminal 43.

(First Cartridge)

As shown in FIG. 3, the first cartridge 20 includes a reservoir 23 for storing an aerosol source 22, the electric load 21 for atomizing the aerosol source 22, a wick 24 for drawing the aerosol source from the reservoir 23 toward the load 21, an aerosol channel 25 for an aerosol generated by atomizing the aerosol source 22 to flow toward the second cartridge 30, and an end cap 26 for storing a part of the second cartridge 30, inside a cylindrical cartridge case 27.

The reservoir 23 is formed so as to surround the aerosol channel 25, and holds the aerosol source 22. In the reservoir 23, a porous member such as a resin web or cotton may be stored, and the porous member may be impregnated with the aerosol source 22. The aerosol source 22 includes a liquid such as glycerin, propylene glycol, or water.

The wick 24 is a liquid holding member for drawing the aerosol source 22 from the reservoir 23 toward the load 21 using capillarity, and is configured with, for example, glass fiber, a porous ceramic, or the like.

The load 21 atomizes the aerosol source 22, without combustion, by power which is supplied from the power supply 12 through the discharging terminal 41. The load 21 is configured with a heating wire wound with a predetermined pitch (a coil). However, the load 21 needs only to be an element capable of atomizing the aerosol source 22, thereby generating an aerosol, and is, for example, a heat generating element or an ultrasonic wave generator. Examples of the heat generating element include a heating resistor, a ceramic heater, an induction heating type heater, and so on.

The aerosol channel 25 is provided on the downstream side of the load 21 on the center line L of the power supply unit 10.

The end cap 26 includes a cartridge storage part 26 a for storing a part of the second cartridge 30, and a connecting passage 26 b for connecting the aerosol channel 25 and the cartridge storage part 26 a.

(Second Cartridge)

The second cartridge 30 holds a flavor source 31. An end part of the second cartridge 30 on the first cartridge (20) side is stored in the cartridge storage part 26 a provided in the end cap 26 of the first cartridge 20, so as to be able to be removed. Another end part of the second cartridge 30 on the opposite side to the first cartridge (20) side is configured as an inhalation port 32 for the user. However, the inhalation port 32 does not necessarily need to be configured integrally with the second cartridge 30 so as not to be separable from the second cartridge, and may be configured to be able to be attached to and detached from the second cartridge 30. If the inhalation port 32 is configured separately from the power supply unit 10 and the first cartridge 20 as described above, it is possible to keep the inhalation port 32 sanitary.

The second cartridge 30 adds a flavor to the aerosol generated by atomizing the aerosol source 22 by the load 21, by passing the aerosol through the flavor source 31. As a raw material piece which constitutes the flavor source, a compact made by forming shredded tobacco or a tobacco raw material into a grain shape can be used. The flavor source 31 may be configured with plants (such as mint, herbal medicines, and herbs) other than tobacco. To the flavor source 31, a flavoring agent such as menthol may be added.

The aerosol inhaler 1 of the present embodiment can generate an aerosol containing the flavor by the aerosol source 22, the flavor source 31, and the load 21. In other words, the aerosol source 22 and the flavor source 31 can be referred to as an aerosol generation source for generating an aerosol.

The configuration of the aerosol generation source which can be used in the aerosol inhaler 1 is not limited to the configuration in which the aerosol source 22 and the flavor source 31 are configured separately, and may be a configuration in which the aerosol source 22 and the flavor source 31 are formed integrally, a configuration in which the flavor source 31 is omitted and the aerosol source 22 contains a substance which can be contained in the flavor source 31, a configuration in which the aerosol source 22 contains a medical substance or the like instead of the flavor source 31, or the like.

In the aerosol inhaler 1 configured as described above, as shown by an arrow B in FIG. 3, air entering from the intake (not shown in the drawings) formed in the power supply unit case 11 passes through the air supply part 42, and passes near the load 21 of the first cartridge 20. The load 21 atomizes the aerosol source 22 drawn from the reservoir 23 by the wick 24. The aerosol generated by atomizing flows through the aerosol channel 25 together with the air entering from the intake, and is supplied to the second cartridge 30 through the connecting passage 26 b. The aerosol supplied to the second cartridge 30 passes through the flavor source 31, whereby the flavor is added, and is supplied to the inhalation port 32.

Also, in the aerosol inhaler 1, the notifying unit 45 for notifying a variety of information is provided (see FIG. 6). The notifying unit 45 may be configured with a light emitting element, or may be configured with a vibrating element, or may be configured with a sound output element. Alternatively, the notifying unit 45 may be a combination of two or more elements of light emitting elements, vibrating elements, and sound output elements. The notifying unit 45 may be provided in any one of the power supply unit 10, the first cartridge 20, and the second cartridge 30; however, it is preferable that the notifying unit be provided in the power supply unit 10. For example, the area around the operation unit 14 is configured to have translucency to permit light which is emitted by light emitting elements such as LEDs to pass through.

(Electric Circuit)

Now, the electric circuit of the power supply unit 10 will be described with reference to FIG. 7.

The power supply unit 10 includes the power supply 12, a positive electrode side discharging terminal 41 a and a negative electrode side discharging terminal 41 b which constitute the discharging terminal 41, a positive electrode side charging terminal 43 a and a negative electrode side charging terminal 43 b which constitute the charging terminal 43, the control unit 50 which is connected between the positive electrode side of the power supply 12 and the positive electrode side discharging terminal 41 a and between the negative electrode side of the power supply 12 and the negative electrode side discharging terminal 41 b, the charger 13 which is disposed on the power transmission path between the charging terminal 43 and the power supply 12, a switch 19 which is disposed on the power transmission path between the power supply 12 and the discharging terminal 41, and a first zener diode 71, a second zener diode 72, a resistor 73, a first capacitor 74, and a second capacitor 75 to be described below. The switch 19 is configured with, for example, a MOSFET, and is turned on and off according to gate voltage which is adjusted by the control unit 50.

(Control Unit)

As shown in FIG. 6, the control unit 50 includes an aerosol generation request detecting unit 51, an operation detecting unit 52, a power control unit 53, and a notification control unit 54.

The aerosol generation request detecting unit 51 detects a request for aerosol generation based on the output result of the inhalation sensor 15. The inhalation sensor 15 is configured to output the value of a variation in the pressure in the power supply unit 10 caused by inhalation of the user through the inhalation port 32. The inhalation sensor 15 is, for example, a pressure sensor for outputting an output value (for example, a voltage value or a current value) according to the atmospheric pressure which varies according to the flow rate of air which is sucked from the intake (not shown in the drawings) toward the inhalation port 32 (i.e. a puff action of the user).

The operation detecting unit 52 detects operations which are performed on the operation unit 14 by the user.

The notification control unit 54 controls the notifying unit 45 such that the notifying unit notifies a variety of information. For example, the notification control unit 54 controls the notifying unit 45 in response to detection of the timing to replace the second cartridge 30, such that the notifying unit notifies the timing to replace the second cartridge 30. The notification control unit 54 notifies the timing to replace the second cartridge 30, based on the number of puff actions or the cumulative time for which power has been supplied to the load 21, stored in the memory 18. The notification control unit 54 is not limited to notification of the timing to replace the second cartridge 30, and may notify the timing to replace the first cartridge 20, the timing to replace the power supply 12, the timing to charge the power supply 12, and so on.

The power control unit 53 controls discharging of the power supply 12 through the discharging terminal 41 by switching on and off the switch 19, if the aerosol generation request detecting unit 51 detects the request for aerosol generation.

The power control unit 53 performs control such that the amount of aerosol which is generated by atomizing the aerosol source by the load 21 falls in a desired range, i.e. such that the amount of power which is supplied from the power supply 12 to the load 21 falls in a predetermined range. Specifically, the power control unit 53 controls switching on and off of the switch 19 by, for example, PWM (Pulse Width Modulation) control. Alternatively, the power control unit 53 may control switching on and off of the switch 19 by PFM (Pulse Frequency Modulation) control.

After supply of power to the load 21 starts, if a predetermined period passes, the power control unit 53 stops supply of power from the power supply 12 to the load 21. In other words, even while the user is actually performing a puff action, if the puff period exceeds a certain period, the power control unit 53 stops supply of power from the power supply 12 to the load 21. The certain period is determined to suppress variation in user's puff period. The power control unit 53 controls the on/off duty ratio of the switch 19 for one puff action, according to the amount of power stored in the power supply 12. For example, the power control unit 53 controls the interval between ON periods in which power is supplied from the power supply 12 to the load 21 (the pulse interval) and controls the length of each ON period in which power is supplied from the power supply 12 to the load 21 (the pulse width).

Also, the power control unit 53 detects an electric connection between the charging terminal 43 and the external power supply 60, and controls charging of the power supply 12 through the charger 13.

(Board Configuration)

As shown in FIG. 5 and FIG. 7, the power supply unit 10 includes a first circuit board 76 on which the charging terminal 43, the second zener diode 72, and the resistor 73 are provided, a second circuit board 77 on which the control unit 50, the charger 13, the switch 19, the first zener diode 71, the first capacitor 74, the second capacitor 75, the operation unit 14, and the inhalation sensor 15 are provided, and a conductive member 78 which electrically connects the first circuit board 76 and the second circuit board 77. The conductive member 78 is a part of a conductor which electrically connects the charging terminal 43 and the charger 13, and the conductive member 78 of the present embodiment is configured with a flexible circuit board; however, it may be configured with a conductive wire.

As shown in FIG. 5, the first circuit board 76 and the second circuit board 77 are disposed apart from each other. Specifically, on one end side of the power supply 12 in the longitudinal direction (the longitudinal direction A), the first circuit board 76 is provided, and on the other end side of the power supply 12 in the longitudinal direction (the longitudinal direction A), the second circuit board 77 is provided, and the first circuit board 76 and the second circuit board 77 are electrically connected through the conductive member 78 extending in the longitudinal direction of the power supply 12 along the periphery of the power supply 12. Alternatively, on one end side of the power supply 12 in the width direction (the direction perpendicular to the longitudinal direction A), the first circuit board 76 may be provided, and on the other end side of the power supply 12 in the width direction, the second circuit board 77 may be provided.

(First Zener Diode)

The first zener diode 71 is provided between the charging terminal 43 and the charger 13 so as to be connected in parallel with the charger 13. According to this first zener diode 71, it is possible to stabilize voltage to be input to the charger 13. In other words, as shown in FIG. 8B, the zener diode has a small breakdown voltage V_(BD) at which current flowing in the backward direction suddenly increases (the backward current prevention action which the diode originally has is lost). Therefore, the zener diode is likely to break down. In this case, as shown in FIG. 8A, the voltage between both ends of the zener diode is fixed at V_(BD), and the relation of Vout (Output Voltage)=V_(BD) is established. Therefore, even though input voltage Vin pulsates as shown in FIG. 8C, stable output voltage Vout without pulsation as shown in FIG. 8D is obtained.

Also, in a circuit shown in FIG. 8A, it should be noted that in the case where voltage which is applied between both ends of the zener diode is lower than the breakdown voltage, the output voltage Vout becomes equal to the input voltage Vin.

The first zener diode 71 is connected closer to the input terminal of the charger 13 than to the output terminal of the charging terminal 43. According to this first zener diode 71, in addition to stabilization of voltage which is supplied from the charging terminal 43, it is possible to eliminate pulsation of the voltage attributable to an L (reactance) component ineluctably existing between the charging terminal 43 and the charger 13, thereby appropriately protecting the charger 13. This ineluctably existing L component is caused by, for example, the conductive member 78 and the resistor 73.

As described above, the first zener diode 71 is provided on the second circuit board 77. In other words, since the charging terminal 43 and the charger 13 are provided on the different circuit boards 76 and 77, the degree of freedom in laying out individual components in the power supply unit 10 is high. Also, since the first zener diode 71 is provided on the second circuit board 77 where the charger 13 is provided, it is possible to dispose the first zener diode 71 close to the charger 13. However, the first zener diode 71 may be provided on the downstream side of the conductive member 78 in the flow direction of power which is input from the charging terminal 43, not on the second circuit board 77. Even in this case, it is possible to dispose the first zener diode 71 close to the charger 13. If the first zener diode is disposed close to the charger 13 as described above, it is possible to input voltage stabilized by eliminating pulsation by the first zener diode 71, to the charger 13.

The first zener diode 71 is directly connected to a bus 79 which electrically connects the charging terminal 43 and the charger 13. In other words, since the first zener diode 71 is connected without a switch such as a transistor interposed therebetween, it is possible to avoid an increase in the size of the structure around the first zener diode 71. Furthermore, in the aerosol inhaler 1, since large current and high voltage are not handled, even if the first zener diode 71 is not connected to a switch such as a transistor, it is possible to sufficiently stabilize voltage.

(Second Zener Diode)

The second zener diode 72 is provided between the charging terminal 43 and the first zener diode 71 so as to be connected in parallel with the first zener diode 71. According to this configuration, while fluctuations in voltage which is input from the external power supply are eliminated by the second zener diode 72, pulsation of the voltage attributable to the L component ineluctably existing between the charging terminal 43 and the charger 13 is eliminated by the first zener diode 71. Therefore, it is possible to more surely protect the charger 13. Also, since different roles are assigned to the first zener diode 71 and the second zener diode 72, it is possible to restrain the sizes and costs of the zener diodes from increasing. Furthermore, it is possible to restrain heat generation from being concentrated in one zener diode. Moreover, since the L component responds to change in voltage or current over time, fluctuations in voltage which is input from the external power supply are eliminated by the second zener diode 72 disposed immediately before the place where the L component occurs. Therefore, it is possible to apply stabler voltage to the charger 13.

As described above, the second zener diode 72 is provided on the first circuit board 76, and the first zener diode 71 is provided on the second circuit board 77 apart from the first circuit board 76. However, the second zener diode 72 may be provided on the upstream side of the conductive member 78 in the flow direction of power which is input from the charging terminal 43, and the first zener diode 71 may be provided on the downstream side of the conductive member 78 in the flow direction of power which is input from the charging terminal 43.

The first zener diode 71 and the second zener diode 72 are configured with identical components. In this case, component management becomes easy, and it is possible to reduce the costs of the zener diodes.

(Zener Voltage)

Now, a range (a zener voltage range) of zener diodes suitable as the second zener diode 72 and the first zener diode 71 will be described with reference to FIG. 9. The zener voltage of a general zener diode is defined as a range which is defined by a minimum value and a maximum value, not as a certain specific value. In the following description, the second zener diode 72 will be described as an example.

The maximum value of the zener voltage of the second zener diode 72 is lower than the maximum operation guarantee voltage (for example, 6.45 V) of the charger 13. According to this configuration, it is possible to avoid voltage equal to or higher than the maximum operation guarantee voltage from being input to the charger 13, and it is possible to stably input voltage lower than the maximum operation guarantee voltage.

The minimum value of the zener voltage of the second zener diode 72 is higher than the minimum operation guarantee voltage (for example, 4.45 V) of the charger 13. According to this configuration, is possible to avoid voltage lower than the minimum operation guarantee voltage from being input to the charger 13, and it is possible to stably input voltage equal to or higher than the minimum operation guarantee voltage.

A value which is obtained by subtracting the maximum value of the zener voltage of the second zener diode 72 from the maximum operation guarantee voltage of the charger 13 is smaller than a value which is obtained by subtracting the minimum operation guarantee voltage of the charger 13 from the minimum value of the zener voltage of the second zener diode 72. According to this configuration, it is possible to lower the frequency at which the second zener diode 72 breaks down. Therefore, it is possible to suppress heat generation of the second zener diode 72, and it is possible to extend the life of the second zener diode 72.

Actually, the resistance values of general zener diodes and currents which flow through the zener diodes in the breakdown state are not small. Therefore, it is preferable that heat generation of zener diodes in the breakdown state should be suppressed. Also, in the case where voltage to be input to the charger 13 is lower than the maximum operation guarantee voltage of the charger 13, stabilization of the voltage by the zener diode is not essential.

The rated value of voltage which can be supplied from the charging terminal 43 (for example, 5.0 V) is higher than the minimum operation guarantee voltage of the charger 13, and the minimum value of the zener voltage of the second zener diode 72 is higher than the rated value of voltage which can be supplied from the charging terminal 43 (the rated voltage). According to this configuration, the second zener diode 72 never breaks down. Therefore, it is possible to efficiently use the second zener diode 72 with respect to voltage which is supplied from the charging terminal 43.

A value which is obtained by subtracting the maximum value of the zener voltage of the second zener diode 72 from the maximum operation guarantee voltage of the charger 13 is smaller than a value which is obtained by the rated value of voltage which can be supplied from the charging terminal 43 from the minimum value of the zener voltage of the second zener diode 72. According to this configuration, it is possible to lower the frequency at which the second zener diode 72 breaks down. Therefore, it is possible to suppress heat generation of the second zener diode 72, and it is possible to extend the life of the second zener diode 72.

For each of components (Z1 to Z5 of FIG. 9) for zener diodes, a minimum value for zener voltage and a maximum value for zener voltage are determined. Therefore, a zener diode having the above-mentioned zener voltage range is selected. Therefore, as the second zener diode 72 and the first zener diode 71, the components Z2 to Z4 are preferable, and the component Z2 is most preferable. In the second zener diode 72 and the first zener diode 71, identical components may be used, or different components may be used.

In the above-described embodiment, in order to stabilize voltage to be input to the charger 13, the second zener diode 72 is used. However, in order to stabilize voltage to be input to the control unit 50, another zener diode may be used. Since the control unit 50 also has a maximum operation guarantee voltage and a minimum operation guarantee voltage similarly to the charger 13, it is possible to use zener diodes having appropriate zener voltage ranges based on them.

(Resistor)

The resistor 73 is provided between the first zener diode 71 and the second zener diode 72 so as to be connected in series with the first zener diode 71 and the second zener diode 72. According to this configuration, since voltage is dropped by the resistor 73, it is possible to prevent high voltage from being input to the charger 13. Furthermore, since voltage equal to or higher than the zener voltage is unlikely to be applied to the first zener diode 71, it is possible to suppress heat generation of the first zener diode 71.

The resistor 73 is connected on the upstream side from the conductive member 78 in the flow direction of power which is input from the charging terminal 43. Specifically, the resistor 73 is provided on the first circuit board 76 apart from the second circuit board 77 on which the charger 13 is provided. According to this configuration, it is possible to separate the resistor 73 which is a heat generating element from the charger 13.

(First Capacitor)

The first capacitor 74 is provided between the charging terminal 43 and the charger 13 so as to be connected in parallel with the charger 13. According to this configuration, it is possible to make the first capacitor 74 function as a smoothing capacitor to stabilize voltage to be input to the charger 13. Also, the first capacitor 74 is connected to the conductor so as to be closer to the charger 13 than to the charging terminal 43. Therefore, it is possible to further stabilize voltage to be input to the charger 13.

Since the resistance component of the conductor electrically connecting the charging terminal 43 and the charger 13 and the first capacitor 74 constitute a low pass filter, it is possible to restrain high-frequency noise from being input to the charger 13. Also, since the first capacitor 74 is provided between the first zener diode 71 and the charger 13 so as to be connected in parallel with the charger 13, minor changes in voltage which cannot be eliminated by the first zener diode are smoothed by the first capacitor 74. Therefore, it is possible to input stabler voltage to the charger 13. Also, in the case of using the above-described resistor 73, the resistor 73 also constitutes a part of the low pass filter.

Therefore, as shown in FIG. 10, the smoothing capacitor smoothes ripple components (pulsation components) included in input voltage Vin, using the charging action and discharging action of the capacitor, thereby stabilizing output voltage Vout. Also, the low pass filter is a filter which is composed of a capacitor (C) and a resistance component (R), as shown in FIG. 11, and removes high-frequency noise, and passes low-frequency noise. The cutoff frequency f of the low pass filter (the maximum frequency of frequencies which the low pass filter passes) is expressed as the following formula.

f=1/2πRC

In order to reduce the area on the circuit board which the first capacitor 74 occupies, it is preferable to reduce the capacity (size) of the first capacitor within such a range that the first capacitor can eliminate ripple components. However, if the capacity of the first capacitor 74 is reduced, the cutoff frequency becomes higher. Therefore, there is a possibility that the first cartridge cannot exhibit sufficient noise removal performance. For this reason, in the power supply unit 10 of the present embodiment, while the capacity of the first capacitor 74 is set to be small, the resistance component is set to be large. As a result, the cutoff frequency is suppressed so as to be low, and necessary noise removal performance is secured. Hereinafter, configurations for setting the resistance component to be large will be listed.

As described above, the first capacitor 74 is provided on the second circuit board 77, together with the charger 13. The second circuit board 77 is apart from the first circuit board 76 on which the charging terminal 43 is provided, and is electrically connected to the first circuit board 76 through the conductive member 78. In other words, on the upstream side of the first capacitor 74, the conductive member 78 exists, and the cutoff frequency becomes low due to the resistance component of the conductive member 78. Therefore, it is possible to improve noise removal performance.

As described above, the first circuit board 76 is provided on one end side of the power supply 12 in the longitudinal direction (or the width direction), and the second circuit board 77 is provided on the other end side of the power supply 12 in the longitudinal direction (or the width direction). In other words, the first circuit board 76 and the second circuit board 77 are provided on the opposite sides of the power supply 12 in the longitudinal direction (or the width direction). Therefore, it is possible to secure the length of the conductive member 78. As a result, it is possible to increase the resistance component of the conductive member 78, thereby lowering the cutoff frequency. In other words, it is possible to widen the frequency band of removable noise.

On the input side of the first capacitor 74, i.e. on the conductor between the first capacitor 74 and the charging terminal 43, the above-mentioned resistor 73 is provided. The resistance component of the resistor 73 lowers the cutoff frequency. Therefore, it is possible to improve noise removal performance. Also, since the resistor 73 drops voltage, it is possible to restrain high voltage from being input to the charger 13. Also, since the resistor 73 is provided on the first circuit board 76, it is possible to decrease the amount of heat generation of the second circuit board 77 on which the charger 13 and the control unit 50 are provided.

According to the above-described configuration, the resistance component is set to be large. Therefore, it is possible to suppress the cutoff frequency so as to be low, and secure necessary noise removal performance.

The capacity of the first capacitor 74 can be set to 1 μF or less. According to this configuration, by selecting a capacitor having sufficient capacity required for the power supply unit 10 for the aerosol inhaler, it is possible to avoid the size of the power supply unit 10 from increasing.

Also, it is preferable that the capacity of the first capacitor 74 should be 0.1 μF or less. According to this configuration, it is possible to reduce the size of the power supply unit 10 while selecting a capacitor having sufficient capacity required for the power supply unit 10 for the aerosol inhaler.

(Second Capacitor)

The second capacitor 75 is connected on the input side of the control unit 50, in parallel with the control unit 50. According to this configuration, by making the second capacitor 75 function as a smoothing capacitor, it is possible to stabilize voltage to be input to the control unit 50. Similarly to the first capacitor 74, the second capacitor 75 also is connected to the conductor so as to be closer to the control unit 50 than to the charging terminal 43. Therefore, it is possible to further stabilize voltage to be input to the control unit 50.

The capacity of the second capacitor 75 is different from the capacity of the first capacitor 74. In other words, since objects (the charger 13 and the control unit 50) which the first capacitor 74 and the second capacitor 75 should protect are different, by selecting capacitors having appropriate capacities according to the objects to be protected, it is possible to reduce the areas on the board which the capacitors occupy.

The maximum operation guarantee voltage of the charger 13 (for example, 6.45 V) is higher than the maximum operation guarantee voltage of the control unit 50 (for example, 5.5 V). For this reason, as the second capacitor 75, a capacitor having a capacity larger than that of the first capacitor 74 is selected. As described above, the capacity of the second capacitor 75 which is provided on the input side of the control unit 50 having low withstand voltage performance is set to be larger than the capacity of the first capacitor 74 which is provided on the input side of the charger 13. Therefore, it is possible to more surely protect the control unit 50 inferior in withstand voltage performance.

The charger 13 is configured to be able to control charging of the power supply 12, and operate only during charging of the power supply 12, and the control unit 50 is configured to operate during charging of the power supply 12 and during discharging of the power supply. Therefore, as the second capacitor 75, a capacitor having a capability larger than that of the first capacitor 74 is selected. As described above, the capacity of the second capacitor 75 which is provided on the input side of the control unit 50 which operations during charging of the power supply 12 and during discharging is set to be larger than the capacity of the first capacitor 74 which is provided on the input side of the charger 13 which operates only during charging. Therefore, it is possible to more surely protect the important control unit 50 to be frequently used.

The control cycle (operation clock) of the charger 13 is longer than the control cycle of the control unit 50. For this reason, as the second capacitor 75, a capacitor having a capacity larger than that of the first capacitor 74 is selected. As described above, the capacity of the second capacitor 75 which is provided on the input side of the control unit 50 having the short control cycle is set to be larger than the capacity of the first capacitor 74 which is provided on the input side of the charger 13 having the long control cycle. Therefore, it is possible to more surely protect the control unit 50 having high performance.

The control unit 50 is electrically connected to the operation unit 14 which the user can operate, and the inhalation sensor 15 for detecting inhaling actions of the user. For this reason, as the second capacitor 75, a capacitor having a capacity larger than that of the first capacitor 74 is selected. According to this configuration, since the capacity of the second capacitor 75 which is provided on the input side of the control unit 50 which is electrically connected to the operation unit 14 and the inhalation sensor 15 is set to be larger than that of the first capacitor 74, it is possible to more surely protect the control unit 50 likely to be influenced by electrostatic noise entering through the operation unit 14 and the inhalation sensor 15.

On the input side of the first capacitor 74, the first zener diode 71 is provided so as to be connected in parallel with the first capacitor 74. Therefore, even if the capacity of the first capacitor 74 is set to be smaller than the capacity of the second capacitor 75, it is possible to protect the charger 13 by the voltage stabilization action of the first zener diode 71.

It is preferable that the capacity of the second capacitor 75 should be 10 times to 100 times the capacity of the first capacitor 74. For example, the capacity of the first capacitor 74 is set to 0.1 μF, and the capacity of the second capacitor 75 is set to 10 μF. As described above, capacitors having appropriate capacities according to objects to be protected are mounted. Therefore, it is possible to reduce the areas on the board which the capacitors occupy while protecting the objects.

(Layout on Second Circuit Board)

As shown in FIG. 3 and FIG. 5, the operation unit 14 and the inhalation sensor 15 are provided on the second circuit board 77. Electrostatic noise such as static electricity entering through the operation unit 14 and the inhalation sensor 15 is smoothed by the capacitors 74 and 75 which are provided on the second circuit board 77.

The second circuit board 77 has a first main surface 77 a, and a second main surface 77 b which is the back of the first main surface 77 a, and the operation unit 14 is provided on the first main surface 77 a, and the inhalation sensor 15 is provided on the second main surface 77 b. As described above, the operation unit 14 and the inhalation sensor 15 are provided on the different surfaces of the second circuit board 77. Therefore, it is possible to restrain electrostatic noise entering through the operation unit 14 and electrostatic noise entering through the inhalation sensor 15 from being superimposed to form large noise.

The capacitors 74 and 75 are provided on the second main surface 77 b of the second circuit board 77. In other words, the second main surface 77 b is a circuit mounting surface. As described above, the capacitors 74 and 75 and the operation unit 14 are provided on the different surfaces of the second circuit board 77. Therefore, it is possible to secure a space for the capacitors 74 and 75 to be disposed.

The operation unit 14 is required to be exposed from the surface of the power supply unit 10 because of its role, so it is likely to become an electrostatic noise entry route. Electrostatic noise is received by the first main surface 77 a, not directly by the second main surface 77 b on which the capacitors 74 and 75 are provided. Therefore, it is possible to restrain electrostatic noise from reaching the second main surface 77 b. Therefore, capacitors having large capacities are unnecessary. Therefore, it is possible to reduce the areas on the board which capacitors occupy.

However, the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. can be made properly.

For example, although the power supply unit 10 of the above-described embodiment has the first zener diode 71 and the second zener diode 72, it may have any one of them.

Also, in the above-described embodiment, with reference to the operation guarantee voltage of the charger 13, an appropriate zener voltage range for the first zener diode 71 and the second zener diode 72 is defined. However, with reference to the operation guarantee voltage of the control unit 50, an appropriate zener voltage range for the first zener diode 71 and the second zener diode 72 may be defined.

In this specification, at least the following inventions (1) to (11) are disclosed. Moreover, although the corresponding constituent elements and the like in the embodiments described above are shown in parentheses, it is not limited thereto.

(1) A power supply unit (the power supply unit 10) for an aerosol inhaler (the aerosol inhaler 1), the power supply unit comprising:

-   -   a power supply (the power supply 12) able to discharge power to         a load (the load 21) for generating an aerosol from an aerosol         source (the aerosol source 22);     -   a connector (the charging terminal 43) able to be electrically         connected to an external power supply (the external power supply         60); and     -   a control device (the control unit 50 and the charger 13)         configured to control at least one of charging and discharging         of the power supply or configured to be able to convert power         which is input from the connector into charging power for the         power supply, wherein     -   the power supply unit further includes a zener diode (the first         zener diode 71 or the second zener diode 72) which is provided         between the connector and the control device so as to be         connected in parallel with the control device, and     -   a maximum value of the zener voltage of the zener diode is lower         than a maximum operation guarantee voltage of the control         device.

According to (1), since the power supply unit includes the zener diode which is provided between the connector and the control device so as to be connected in parallel with the control device, it is possible to stabilize voltage to be input to the control device. Also, since the maximum value of the zener voltage of the zener diode is lower than the maximum operation guarantee voltage of the control device, it is possible to avoid voltage equal to or higher than the maximum operation guarantee voltage from being input to the control device, and it is possible to stably input voltage lower than the maximum operation guarantee voltage.

(2) The power supply unit according to (1), wherein

-   -   a minimum value of the zener voltage of the zener diode is         higher than a minimum operation guarantee voltage of the control         device.

According to (2), since the minimum value of the zener voltage of the zener diode is higher than the minimum operation guarantee voltage of the control device, it is possible to avoid voltage lower than the minimum operation guarantee voltage from being input to the control device, and it is possible to stably input voltage equal to or higher than the minimum operation guarantee voltage.

(3) The power supply unit according to (2), wherein

-   -   a value which is obtained by subtracting the maximum value of         the zener voltage of the zener diode from the maximum operation         guarantee voltage of the control device is smaller than a value         which is obtained by subtracting the minimum operation guarantee         voltage of the control device from the minimum value of the         zener voltage of the zener diode.

According to (3), since the value which is obtained by subtracting the maximum value of the zener voltage of the zener diode from the maximum operation guarantee voltage of the control device is smaller than the value which is obtained by subtracting the minimum operation guarantee voltage of the control device from the minimum value of the zener voltage of the zener diode, it is possible to lower the frequency at which the zener diode breaks down. Therefore, it is possible to suppress heat generation of the zener diode, and it is possible to expend the life of the zener diode.

(4) The power supply unit according to (1), wherein

-   -   a rated value for voltage which is supplied from the connector         is higher than a minimum operation guarantee voltage of the         control device, and     -   a minimum value of the zener voltage of the zener diode is         higher than the rated value.

According to (4), since the minimum value of the zener voltage of the zener diode is higher than the minimum operation guarantee voltage of the control device, and is higher than the rated value for voltage which can be supplied from the connector, it is possible to effectively use the zener diode with respect to voltage which is supplied from the connector.

(5) The power supply unit according to (4), wherein

-   -   a value which is obtained by subtracting the maximum value of         the zener voltage of the zener diode from the maximum operation         guarantee voltage of the control device is smaller than a value         which is obtained by subtracting the rated value for the voltage         which is supplied from the connector from the minimum value of         the zener voltage of the zener diode.

According to (5), since the value which is obtained by subtracting the maximum value of the zener voltage of the zener diode from the maximum operation guarantee voltage of the control device is smaller than the value which is obtained by subtracting the rated value for the voltage which is supplied from the connector from the minimum value of the zener voltage of the zener diode, it is possible to lower the frequency at which the zener diode breaks down. Therefore, it is possible to suppress heat generation of the zener diode, and it is possible to expend the life of the zener diode.

(6) The power supply unit according to any one of (1) to (5), wherein

-   -   the power supply unit further includes:         -   a first circuit board (the first circuit board 76) on which             the connector is provided; and         -   a second circuit board (the second circuit board 77) which             is apart from the first circuit board and on which the             control device is provided, and     -   the zener diode is provided on the first circuit board.

According to (6), since the connector and the control device are provided on the different circuit boards, the degree of freedom in layout is high. Furthermore, although an L component ineluctably existing between the two circuit boards responds to change in voltage or current over time, fluctuations in voltage are eliminated by the zener diode disposed immediately before the place where the L component occurs. Therefore, it is possible to more surely protect the control device.

(7) The power supply unit according to (6), wherein

-   -   the power supply unit further includes a resistor (the resistor         73) which is provided on the first circuit board so as to be         connected in series with the connector and the zener diode.

According to (7), in the power supply unit, the resistor is provided on the first circuit board so as to be connected in series with the connector and the zener diode. Therefore, the resistor drops voltage. Therefore, it is possible to prevent high voltage from being input to the control device.

(8) The power supply unit according to (7), wherein

-   -   the resistor is connected between the control device and the         zener diode.

According to (8), since the resistor is connected between the control device and the zener diode, it is possible to further drop voltage stabilized by the zener diode, by the resistor. Therefore, it is possible to input stabler voltage to the control device.

(9) The power supply unit according to any one of (6) to (8), wherein

-   -   the power supply unit further includes a conductive member (the         conductive member 78) which electrically connects the first         circuit board and the second circuit board.

According to (9), since the conductive member is provided in the power supply unit so as to electrically connect the first circuit board and the second circuit board, voltage is dropped by the conductive member. Therefore, it is possible to prevent high voltage from being input to the control device.

(10) The power supply unit according to any one of (6) to (9), wherein

-   -   the power supply unit further includes a capacitor (the first         capacitor 74 or the second capacitor 75) which is provided         between the zener diode and the control device so as to be         connected in parallel with the control device.

According to (10), since the power supply unit further includes the capacitor which is provided between the zener diode and the control device so as to be connected in parallel with the control device, it is possible to smooth minor changes in voltage which cannot be eliminated by the zener diode, and it is possible to more appropriately protect the control device.

(11) The power supply unit according to (10), wherein

-   -   the capacitor is provided on the second circuit board.

According to (11), since the capacitor is provided on the second circuit board, it is possible to integrate the zener diode, the capacitor, and the control device into the second circuit board. 

What is claimed is:
 1. A power supply unit for an aerosol inhaler, the power supply unit comprising: a power supply able to discharge power to a load for generating an aerosol from an aerosol source; a connector able to be electrically connected to an external power supply; a control device configured to control at least one of charging and discharging of the power supply or configured to be able to convert power which is input from the connector into charging power for the power supply; and a zener diode provided between the connector and the control device so as to be connected in parallel with the control device, wherein a maximum value of zener voltage of the zener diode is lower than a maximum operation guarantee voltage of the control device, a minimum value of the zener voltage of the zener diode is higher than a minimum operation guarantee voltage of the control device, and a value which is obtained by subtracting the maximum value of the zener voltage of the zener diode from the maximum operation guarantee voltage of the control device is smaller than a value which is obtained by subtracting the minimum operation guarantee voltage of the control device from the minimum value of the zener voltage of the zener diode.
 2. The power supply unit according to claim 1, wherein the power supply unit further includes: a first circuit board on which the connector is provided; and a second circuit board which is apart from the first circuit board and on which the control device is provided, and the zener diode is provided on the first circuit board.
 3. The power supply unit according to claim 2, wherein the power supply unit further includes a resistor which is provided on the first circuit board so as to be connected in series with the connector and the zener diode.
 4. The power supply unit according to claim 3, wherein the resistor is connected between the control device and the zener diode.
 5. The power supply unit according to claim 2, wherein the power supply unit further includes a conductive member which electrically connects the first circuit board and the second circuit board.
 6. The power supply unit according to claim 2, wherein the power supply unit further includes a capacitor which is provided between the zener diode and the control device so as to be connected in parallel with the control device.
 7. The power supply unit according to claim 6, wherein the capacitor is provided on the second circuit board.
 8. A power supply unit for an aerosol inhaler, the power supply unit comprising: a power supply able to discharge power to a load for generating an aerosol from an aerosol source; a connector able to be electrically connected to an external power supply; a control device configured to control at least one of charging and discharging of the power supply or configured to be able to convert power which is input from the connector into charging power for the power supply; and a zener diode provided between the connector and the control device so as to be connected in parallel with the control device, wherein a maximum value of zener voltage of the zener diode is lower than a maximum operation guarantee voltage of the control device, a rated value for voltage which is supplied from the connector is higher than a minimum operation guarantee voltage of the control device, a minimum value of the zener voltage of the zener diode is higher than the rated value, and a value which is obtained by subtracting the maximum value of the zener voltage of the zener diode from the maximum operation guarantee voltage of the control device is smaller than a value which is obtained by subtracting the rated value for the voltage which is supplied from the connector from the minimum value of the zener voltage of the zener diode.
 9. The power supply unit according to claim 8, wherein the power supply unit further includes: a first circuit board on which the connector is provided; and a second circuit board which is apart from the first circuit board and on which the control device is provided, and the zener diode is provided on the first circuit board.
 10. The power supply unit according to claim 9, wherein the power supply unit further includes a resistor which is provided on the first circuit board so as to be connected in series with the connector and the zener diode.
 11. The power supply unit according to claim 10, wherein the resistor is connected between the control device and the zener diode.
 12. The power supply unit according to claim 9, wherein the power supply unit further includes a conductive member which electrically connects the first circuit board and the second circuit board.
 13. The power supply unit according to claim 9, wherein the power supply unit further includes a capacitor which is provided between the zener diode and the control device so as to be connected in parallel with the control device.
 14. The power supply unit according to claim 13, wherein the capacitor is provided on the second circuit board. 